TCP transports are connection-oriented and every call arriving on
such a transport will use the same per-client stats entry. So we
can avoid doing a hash lookup in a locked global hashtable on every
NFS call by caching the result of nfsd_stats_find() on the transport.
The same is true of RDMA transports, but this patch doesn't address
that.
Signed-off-by: Greg Banks <[email protected]>
---
fs/nfsd/stats.c | 45 ++++++++++++++++++++++++++---
include/linux/sunrpc/svc_xprt.h | 3 +
net/sunrpc/svc_xprt.c | 4 ++
net/sunrpc/svcsock.c | 1
4 files changed, 49 insertions(+), 4 deletions(-)
Index: bfields/fs/nfsd/stats.c
===================================================================
--- bfields.orig/fs/nfsd/stats.c
+++ bfields/fs/nfsd/stats.c
@@ -394,6 +394,39 @@ static void __nfsd_stats_op(struct svc_r
os->os_ops[op]++;
}
+static inline nfsd_stats_hentry_t *
+nfsd_stats_xprt_cached_get(struct svc_rqst *rqstp)
+{
+ struct svc_xprt *xprt = rqstp->rq_xprt;
+ nfsd_stats_hentry_t *se = NULL;
+
+ if (test_bit(XPT_CACHE_STATS, &xprt->xpt_flags)) {
+ spin_lock(&xprt->xpt_lock);
+ se = xprt->xpt_stats_cache;
+ if (se != NULL)
+ nfsd_stats_get(se);
+ spin_unlock(&xprt->xpt_lock);
+ }
+ return se;
+}
+
+static inline void
+nfsd_stats_xprt_cached_set(struct svc_rqst *rqstp, nfsd_stats_hentry_t *se)
+{
+ struct svc_xprt *xprt = rqstp->rq_xprt;
+
+ if (test_bit(XPT_CACHE_STATS, &xprt->xpt_flags)) {
+ spin_lock(&xprt->xpt_lock);
+ if (xprt->xpt_stats_cache == NULL) {
+ xprt->xpt_stats_cache = se;
+ xprt->xpt_stats_cache_release = (void (*)(void*))nfsd_stats_put;
+ /* take a reference for the cached pointer */
+ nfsd_stats_get(se);
+ }
+ spin_unlock(&xprt->xpt_lock);
+ }
+}
+
void nfsd_stats_update_op(struct svc_rqst *rqstp, struct svc_fh *fh,
int rbucket, int wbucket, int op)
{
@@ -424,10 +457,14 @@ void nfsd_stats_update_op(struct svc_rqs
/* first op in the call: find and cache per-client stats */
if (rqstp->rq_client_stats == NULL) {
char *client, buf[SVC_FORMAT_ADDR_MAX];
- se = NULL;
- client = __svc_format_addr(svc_addr(rqstp), buf, sizeof(buf));
- if (client != NULL)
- se = nfsd_stats_find(&nfsd_client_stats_hash, client, strlen(client));
+ se = nfsd_stats_xprt_cached_get(rqstp);
+ if (se == NULL) {
+ client = __svc_format_addr(svc_addr(rqstp), buf, sizeof(buf));
+ if (client != NULL)
+ se = nfsd_stats_find(&nfsd_client_stats_hash, client, strlen(client));
+ if (se != NULL)
+ nfsd_stats_xprt_cached_set(rqstp, se);
+ }
if (se != NULL) {
/* take over the new reference from nfsd_stats_find() */
rqstp->rq_client_stats = se;
Index: bfields/include/linux/sunrpc/svc_xprt.h
===================================================================
--- bfields.orig/include/linux/sunrpc/svc_xprt.h
+++ bfields/include/linux/sunrpc/svc_xprt.h
@@ -51,6 +51,7 @@ struct svc_xprt {
#define XPT_DETACHED 10 /* detached from tempsocks list */
#define XPT_LISTENER 11 /* listening endpoint */
#define XPT_CACHE_AUTH 12 /* cache auth info */
+#define XPT_CACHE_STATS 13 /* cache stats info */
struct svc_pool *xpt_pool; /* current pool iff queued */
struct svc_serv *xpt_server; /* service for transport */
@@ -59,6 +60,8 @@ struct svc_xprt {
spinlock_t xpt_lock; /* protects sk_deferred
* and xpt_auth_cache */
void *xpt_auth_cache;/* auth cache */
+ void *xpt_stats_cache;
+ void (*xpt_stats_cache_release)(void *);
struct list_head xpt_deferred; /* deferred requests that need
* to be revisted */
struct sockaddr_storage xpt_local; /* local address */
Index: bfields/net/sunrpc/svc_xprt.c
===================================================================
--- bfields.orig/net/sunrpc/svc_xprt.c
+++ bfields/net/sunrpc/svc_xprt.c
@@ -130,6 +130,10 @@ static void svc_xprt_free(struct kref *k
if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags)
&& xprt->xpt_auth_cache != NULL)
svcauth_unix_info_release(xprt->xpt_auth_cache);
+ if (test_bit(XPT_CACHE_STATS, &xprt->xpt_flags) &&
+ xprt->xpt_stats_cache != NULL &&
+ xprt->xpt_stats_cache_release != NULL)
+ xprt->xpt_stats_cache_release(xprt->xpt_stats_cache);
xprt->xpt_ops->xpo_free(xprt);
module_put(owner);
}
Index: bfields/net/sunrpc/svcsock.c
===================================================================
--- bfields.orig/net/sunrpc/svcsock.c
+++ bfields/net/sunrpc/svcsock.c
@@ -1108,6 +1108,7 @@ static void svc_tcp_init(struct svc_sock
svc_xprt_init(&svc_tcp_class, &svsk->sk_xprt, serv);
set_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
+ set_bit(XPT_CACHE_STATS, &svsk->sk_xprt.xpt_flags);
if (sk->sk_state == TCP_LISTEN) {
dprintk("setting up TCP socket for listening\n");
set_bit(XPT_LISTENER, &svsk->sk_xprt.xpt_flags);
--
Greg